This site is the blogging component for my main site Crank Astronomy (formerly "Dealing with Creationism in Astronomy"). It will provide a more interactive component for discussion of the main site content. I will also use this blog to comment on work in progress for the main site, news events, and other pseudoscience-related issues.

Figure 1: One energy band of the IBEX all-sky map, corresponding to atoms with an energy of around 1,100 electron volts. The different colors correspond to different counts of atoms from the different directions in the sky (note the color bar at bottom). The 'nose' of the heliosphere, the direction of the Sun's motion relative to the local interstellar medium, corresponds to the center of the map. This map, A, is the entire sky projected into 2-dimensions, using an Aitoff projection (Wikipedia: Aitoff Projection). The inset, B, reveals bright knots in the ribbon. Credit: SwRI. More images from the NASA press release.

IBEX sees a clear enhancement in the direction of the Sun's motion through the interstellar medium (ISM). In the skymap, this flux appears as blue, corresponding to a value of about 100 particles per square centimeter/second/steradian/keV. This enhancement was expected by the standard model of the Sun's magnetic field interacting with the interstellar medium, much the same way as the Earth's magnetic field interacts with the solar wind to form the magnetosphere (Wikipedia: Magnetosphere).

The unexpected result is the 'ribbon'-like structure seen to stretch across the maps. This enhancement corresponds to a particle flux up to three times higher than the regular flux in the Sun's direction of motion.

This feature, which appears on a full sky survey, was undetected by the two Voyager spacecraft which just happened to pass to each side of the 'ribbon'. This illustrates the limitations of in situ measurements when compared to large-scale, surveys. This is why real science tries to incorporate both types of measurements.

The press releases emphasizes the surprising aspects of the result:

"This is a shocking new result," says IBEX principal investigator Dave McComas of the Southwest Research Institute. "We had no idea this ribbon existed--or what has created it. Our previous ideas about the outer heliosphere are going to have to be revised."

"We're missing some fundamental aspect of the interaction between the heliosphere and the rest of the galaxy. Theorists are working like crazy to figure this out."

Interpretations
But the problem for heliospheric physics not as big as the enthusiastic wording of a NASA press release might suggest. Such phrasing is popular among public affairs offices as it promotes science as an exciting field, but such phrasing is also fodder for crank science groups, who always like to claim their model predicted the result all along. More on this aspect below.

The region of the ribbon on the sky agrees well with predictions of existing 3-D heliospheric models, if there is an additional interaction of the current, induced in the plasma by the interstellar magnetic field, with the magnetic field itself. This is called the JxB current (see “Comparison of Interstellar Boundary Explorer Observations with 3D Global Heliospheric Models”, Schwandron et al.). That the inclusion of the JxB term (which has units of a pressure) exhibits such excellent agreement with the intensity profile of the ribbon suggests there is an additional particle interaction at play which has not been included in standard heliospheric models. This is possibly another indicator that magnetospheric MHD models have reached the limits of their ability to generate robust predictions in the era of modern instruments and more effort should be directed in developing models which more accurately treat the particle kinetics (see "Hybrid Simulation Codes: Past, Present and Future - A Tutorial").

As usual, the comments from the EU fan club are scientifically useless, resembling a form of electrophilic pareidolia (Wikipedia: pareidolia). Everything looks like some type of current to them.

So let's go into the reasons why the IBEX result creates more problems for the EU claims that the Sun is powered by external electrical energy.

1) IBEX reports a flux of Sunward-bound NEUTRAL atoms. Not charged atoms, and not electrons (as required by many Electric Sun models). In the forty years that humans have sent satellites ranging between the orbit of Mercury to the termination shock, no space plasma detector has detected Sunward-bound electrons at anywhere near the flux and energies needed to provide significant power the Sun by this method.

2) This result indicates the heliopause is not a uniform region on fairly large scales. So how can a flux of electrons from the heliopause create a sun that radiates so uniformly? Consider the three possibilities:

Electrons on direct radial paths from the heliopause to the photosphere would imprint this 'ribbon' structure on the phosphere. The flux difference is a factor of two or three, so we would see an 'imprint' of this feature on the photosphere. Why don't we see this enhancement in solar brightness?

Suppose the electrons have their directions slightly randomized during their infall, so they hit the photosphere in a uniform flow, washing out the imprint of the IBEX 'ribbon'. In that case, sunward electron fluxes should be about the same from any direction centered on the Sun. This means the measured electrons fluxes from spacecraft would be consistent with values mentioned in my analysis of the "Solar Capacitor Model" (see 1, 2, 3).

The infalling electron flow, through randomization and electromagnetic focusing, gets confined to streamers. The popular plasma lamp configuration (Wikipedia: Plasma Lamp) illustrates how such energetic streamers will create localized heating regions on surface, again, contrary to our observations of the Sun.

The only way the Sun could receive its energy from external particle flows, electrons or otherwise, is if electrons have some physics-defying properties yet to be detected in laboratories in our 100+ years of experience with them in scientific and engineering applications.

An 'Official Word' from the Electric Universe Priesthood?
Shortly after I had prepared the response above, I received news of the 'official' spin being placed on the IBEX results by advocates of the 'Electric Universe': "Electric Sun Verified" by Wal Thornhill

Thornhill claims the 'ribbon' seen by IBEX fits the 'Electric Stars' model perfectly? He includes several 'predictions' that are about as insightful and precise as a tabloid psychic.

As part of this article, Thornhill included an interesting graphic about halfway down the page titled “The Sun's Environment”. Close examination of this graphic and the accompanying text reveals that it is yet another Electric Sun model, with a some features, or at least ambiguities, substantially different than those presented in the Electric Sun models of “The Electric Sky” and other EU resources.

Of course, if EU was really doing science, they would apply Maxwell's equations to the current systems they propose and see what happens for themselves. But that might be expecting too much of them. Plus, it's much more entertaining to demonstrate how they don't understand the basics of the physics in which they claim expertise!

More to come...

Thanks to Nathan Schwadron (Boston U & Southwest Research Institute) for clarifying some of my questions in interpreting their paper.

Tuesday, October 13, 2009

“Open” magnetic field lines is another concept that Dr. Scott condemns (”The Electric Sky”, page 118; “D.E. Scott Rebuts T. Bridgman: Open Magnetic Field Lines'', pg 11), but like so many other of his claims, he is, at best, playing semantic games. In principle, magnetic and electric field lines can extend to infinity, however, in most cases we wish to examine, we don't want or need to consider the behavior at infinity. Is Dr. Scott saying that any time you want to visualize something with a magnetic field, you must represent the entire universe?

In any real analysis, we have to draw the boundary somewhere. This can leave field lines cut-off. Particles can still flow along these lines. In general, they will connect to field lines from another field of a more distant source. In the case of magnetic dipole fields, these 'open' lines generally occur near the poles. If Dr. Scott claims these lines don't exist, is he claiming that charged particles cannot travel out from these regions? Where do the charged particles go?

The recognition that magnetic field lines can never end is acknowledged by many researchers by enclosing the term 'open' in quotes. I will use that convention here.

Dr. Scott's obsession with 'open' field lines also reveals an hypocrisy on his part. It's as if he wants to treat them as 'real', in need of being drawn 'complete'. But Dr. Scott's claim gets even stranger when we begin to explore his justification that 'open' field lines violate Maxwell's equations [Scott 2007]. Specifically, Scott claims that field lines must be closed to satisfy the Maxwell Equation,

But magnetic field lines are not 'real', they are representations of a vector field designed as mere guides to directions of charged particle flow, representing the direction of the vector field at that point. When we draw a field line as complete between two points, say A and B, (See Figure 1 at below) we are saying that we expect the particles moving outward from point A will eventually arrive at point B. If a field line is 'open', such as for point C, we don't expect the particle to ever return to the original system, such as point D, but connect to magnetic fields from other more distant sources. Dr. Scott's insistence on closed magnetic field lines makes such systems of plasmas permanently CLOSED to any kind of charged particle transfer.

Figure 1: An exploration of closed and 'open' field lines. The red field lines close back on the source object for the field. The blue field lines are 'open', connecting to more distant field sources which we don't show in this graphic.

The Maxwell equation,

, is true everywhere in a magnetic field. This is a consequence of what is called the Divergence Theorem and is related to the observational evidence that there are no (known) magnetic monopoles (source points of magnetic flux) and it means that the net magnetic flux passing through a closed surface is zero: the same amount of magnetic flux passes into the surface as passes out of it. This condition demands no other constraint!

In fact, the simplest set of 'open' field lines, a constant magnetic field, where the field lines extend from points at 'negative infinite distance' to 'positive infinite distance', trivially satisfies the divergence condition. Dr. Scott's claim that 'open' field lines violate the divergence condition for magnetic fields is false by trivial counter example! An undergraduate physics major taking a year course in electromagnetism should immediately recognize Dr. Scott's statement as a gross error.

The really embarassing part is that Dr. Scott managed to get this fundamentally erroneous claim into the IEEE Transactions on Plasma Science, a journal that is supposed to be peer-reviewed! This wasn't an obscure paragraph in the paper. A large section of the paper was devoted to arguing this statement. The journal allowed a blooper like this through? What does that say about the quality of the peer-review process for this journal?

The only problem with this is that the applicable vector identity is Stokes Theorem, so

This mathematical relationship is true for any arbitrary closed path in the magnetic field, such as path EFGH, or even IJKL, in Figure 1. It is not just paths representing magnetic field 'lines'! What we define as magnetic field lines are just lines defined along a path parallel to the local vector field, so that the line segment, dl, is parallel to the magnetic vector, B.

There is no requirement that the path be closed when defining magnetic field lines, only that if the path is closed, by Stoke's Theorem, it will specify some characteristic of the current and electric field passing through the surface enclosed by the path.

While drawing field lines as closed loops will guarantee that

insistence on 'close' field lines appears to be a human convention not tied to any physical requirement so long as the magnetic field lines never begin or end (Wikipedia: Magnetic Fields).

As an additional check, I've examined a number of papers written in the past 100 years on the development of electromagnetism and on magnetic fields and field lines, many written by leaders in the field, including works by Alfven, Vasyliunas, Stern, Swann, and Falthammar, and have found no support for Scott's statements that field lines cannot be 'open'. Many of these researchers use the concept themselves. If Dr. Scott wishes to continue making this particular claim, he needs to provide more documentation than "Don Scott Says So". Professionals with a stronger background in electromagnetism than Dr. Scott (or me), disagree with him.

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About Me

I obtained my doctorate in physics and astronomy in 1994. I currently work in scientific data visualization for the media and public outreach. For more information on how I became involved in the creationism issue, visit my main page